I already did this in post #99. Then you asked (in post #102) where I did this, and in post #108, I referred you to that post. (like in another thread on the Crusades you’re happy to contiually ask for evidence already given)
So here it is (again).
That’s the whole reason to say it’s a ‘double procession’. The Catholic Encyclopaedia takes “procession” as being a point of origin…
“We need not dwell at length on the precise meaning of the Procession in God. (See TRINITY.) It will suffice here to remark that by this word we mean the relation of origin that exists between one Divine Person and another, or between one and the two others as its principle of origin. The Son proceeds from the Father; the Holy Ghost proceeds from the Father and the Son…”
newadvent.org/cathen/07409a.htm
That is, as the Father is the eternal source of the Holy Spirit, the Son, being all that the Father is (except being ‘the Father’) must also be the eternal source of the Holy Spirit.
Here it is in the Catechism…
246 The Latin tradition of the Creed confesses that the Spirit “proceeds from the Father and the Son (filioque)”. The Council of Florence in 1438 explains: “The Holy Spirit is eternally from Father and Son; He has his nature and subsistence at once (simul) from the Father and the Son. He proceeds eternally from both as from one principle and through one spiration. . . . And, since the Father has through generation given to the only-begotten Son everything that belongs to the Father, except being Father, the Son has also eternally from the Father, from whom he is eternally born, that the Holy Spirit proceeds from the Son.”
scborromeo.org/ccc/para/246.htm
As from one principle, because the Son is all that the Father is!
Go on! Ask me again!